Multi-objective optimization method for magnetic media pre-bulging process parameters of spherical bottom cylindrical parts based on response surface

Abstract

In order to improve the magnetic medium-assisted deep drawing forming performance of the spherical bottom cylindrical parts, the uniformity of deformation can be improved by pre-bulging at the initial stage of deep drawing, but the pre-bulging process of magnetic medium is complex and has many influencing factors. To solve this problem, the grey relational analysis and response surface optimization method are proposed to optimize the experimental parameters. The design variables are pre-bulging height, magnetic field strength, friction coefficient and blank holder clearance. At the same time, the forming height and the maximum thinning rate of wall thickness of parts are optimized by multi-objective method. After optimization, the final ideal parameters are: pre-bulging height 6.1 mm, magnetic field strength 0.2 T, friction coefficient 0.06, blank holder clearance 0.1 mm. The comparison shows that the error between the experimental and predicted results of forming height is only 0.16%, and the error between the experimental and predicted results of maximum thinning rate is only 3.98%. The reliability of the prediction model is fully proved, which provides scientific guidance for improving the quality of magnetic medium aided forming of thin-walled deep-cavity sheet metal components. Keywords: Magnetic medium, Pre-bulging, Grey relational analysis, Response surface methodology, Multi-objective optimization